linux-stable.git/drivers/clocksource, branch v4.4.201

clocksource/drivers/exynos_mct: Clear timer interrupt when shutdown

2019-03-23T07:44:35+00:00

commit d2f276c8d3c224d5b493c42b6cf006ae4e64fb1c upstream.

When shutting down the timer, ensure that after we have stopped the
timer any pending interrupts are cleared. This fixes a problem when
suspending, as interrupts are disabled before the timer is stopped,
so the timer interrupt may still be asserted, preventing the system
entering a low power state when the wfi is executed.

Signed-off-by: Stuart Menefy 
Reviewed-by: Krzysztof Kozlowski 
Tested-by: Marek Szyprowski 
Cc:  # v4.3+
Signed-off-by: Daniel Lezcano 
Signed-off-by: Greg Kroah-Hartman

clocksource/drivers/exynos_mct: Move one-shot check from tick clear to ISR

2019-03-23T07:44:35+00:00

commit a5719a40aef956ba704f2aa1c7b977224d60fa96 upstream.

When a timer tick occurs and the clock is in one-shot mode, the timer
needs to be stopped to prevent it triggering subsequent interrupts.
Currently this code is in exynos4_mct_tick_clear(), but as it is
only needed when an ISR occurs move it into exynos4_mct_tick_isr(),
leaving exynos4_mct_tick_clear() just doing what its name suggests it
should.

Signed-off-by: Stuart Menefy 
Reviewed-by: Krzysztof Kozlowski 
Tested-by: Marek Szyprowski 
Cc: stable@vger.kernel.org # v4.3+
Signed-off-by: Daniel Lezcano 
Signed-off-by: Greg Kroah-Hartman

clockevents/drivers/i8253: Add support for PIT shutdown quirk

2018-11-21T08:27:42+00:00

commit 35b69a420bfb56b7b74cb635ea903db05e357bec upstream.

Add support for platforms where pit_shutdown() doesn't work because of a
quirk in the PIT emulation. On these platforms setting the counter register
to zero causes the PIT to start running again, negating the shutdown.

Provide a global variable that controls whether the counter register is
zero'ed, which platform specific code can override.

Signed-off-by: Michael Kelley 
Signed-off-by: Thomas Gleixner 
Cc: "gregkh@linuxfoundation.org" 
Cc: "devel@linuxdriverproject.org" 
Cc: "daniel.lezcano@linaro.org" 
Cc: "virtualization@lists.linux-foundation.org" 
Cc: "jgross@suse.com" 
Cc: "akataria@vmware.com" 
Cc: "olaf@aepfle.de" 
Cc: "apw@canonical.com" 
Cc: vkuznets 
Cc: "jasowang@redhat.com" 
Cc: "marcelo.cerri@canonical.com" 
Cc: KY Srinivasan 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1541303219-11142-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Greg Kroah-Hartman

clocksource/drivers/ti-32k: Add CLOCK_SOURCE_SUSPEND_NONSTOP flag for non-am43 SoCs

2018-10-20T07:52:37+00:00

[ Upstream commit 3b7d96a0dbb6b630878597a1838fc39f808b761b ]

The 32k clocksource is NONSTOP for non-am43 SoCs. Hence
add the flag for all the other SoCs.

Reported-by: Tony Lindgren 
Signed-off-by: Keerthy 
Acked-by: Tony Lindgren 
Signed-off-by: Daniel Lezcano 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

clocksource/drivers/fsl_ftm_timer: Fix error return checking

2018-05-30T05:49:01+00:00

[ Upstream commit f287eb9013ccf199cbfa4eabd80c36fedfc15a73 ]

The error checks on freq for a negative error return always fails because
freq is unsigned and can never be negative. Fix this by making freq a
signed long.

Detected with Coccinelle:
drivers/clocksource/fsl_ftm_timer.c:287:5-9: WARNING: Unsigned expression
compared with zero: freq <= 0
drivers/clocksource/fsl_ftm_timer.c:291:5-9: WARNING: Unsigned expression
compared with zero: freq <= 0

Fixes: 2529c3a33079 ("clocksource: Add Freescale FlexTimer Module (FTM) timer support")
Signed-off-by: Colin Ian King 
Signed-off-by: Thomas Gleixner 
Cc: Daniel Lezcano 
Cc: kernel-janitors@vger.kernel.org
Link: https://lkml.kernel.org/r/20180226113614.3092-1-colin.king@canonical.com
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

clockevents/drivers/cs5535: Improve resilience to spurious interrupts

2017-10-27T08:23:17+00:00

commit eb39a7c0355393c5a8d930f342ad7a6231b552c4 upstream.

The interrupt handler mfgpt_tick() is not robust versus spurious interrupts
which happen before the clock event device is registered and fully
initialized.

The reason is that the safe guard against spurious interrupts solely checks
for the clockevents shutdown state, but lacks a check for detached
state. If the interrupt hits while the device is in detached state it
passes the safe guard and dereferences the event handler call back which is
NULL.

Add the missing state check.

Fixes: 8f9327cbb6e8 ("clockevents/drivers/cs5535: Migrate to new 'set-state' interface")
Suggested-by: Thomas Gleixner 
Signed-off-by: David Kozub 
Signed-off-by: Thomas Gleixner 
Cc: Daniel Lezcano 
Link: https://lkml.kernel.org/r/20171020093103.3317F6004D@linux.fjfi.cvut.cz
Signed-off-by: Greg Kroah-Hartman

clocksource/exynos_mct: Clear interrupt when cpu is shut down

2017-01-26T07:23:48+00:00

commit bc7c36eedb0c7004aa06c2afc3c5385adada8fa3 upstream.

When a CPU goes offline a potentially pending timer interrupt is not
cleared. When the CPU comes online again then the pending interrupt is
delivered before the per cpu clockevent device is initialized. As a
consequence the tick interrupt handler dereferences a NULL pointer.

[   51.251378] Unable to handle kernel NULL pointer dereference at virtual address 00000040
[   51.289348] task: ee942d00 task.stack: ee960000
[   51.293861] PC is at tick_periodic+0x38/0xb0
[   51.298102] LR is at tick_handle_periodic+0x1c/0x90

Clear the pending interrupt in the cpu dying path.

Fixes: 56a94f13919c ("clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier")
Reported-by: Seung-Woo Kim 
Signed-off-by: Joonyoung Shim 
Cc: linux-samsung-soc@vger.kernel.org
Cc: cw00.choi@samsung.com
Cc: daniel.lezcano@linaro.org
Cc: javier@osg.samsung.com
Cc: kgene@kernel.org
Cc: krzk@kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1484628876-22065-1-git-send-email-jy0922.shim@samsung.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

clocksource/drivers/sun4i: Clear interrupts after stopping timer in probe function

2016-09-24T08:07:35+00:00

commit b53e7d000d9e6e9fd2c6eb6b82d2783c67fd599e upstream.

The bootloader (U-boot) sometimes uses this timer for various delays.
It uses it as a ongoing counter, and does comparisons on the current
counter value. The timer counter is never stopped.

In some cases when the user interacts with the bootloader, or lets
it idle for some time before loading Linux, the timer may expire,
and an interrupt will be pending. This results in an unexpected
interrupt when the timer interrupt is enabled by the kernel, at
which point the event_handler isn't set yet. This results in a NULL
pointer dereference exception, panic, and no way to reboot.

Clear any pending interrupts after we stop the timer in the probe
function to avoid this.

Signed-off-by: Chen-Yu Tsai 
Signed-off-by: Daniel Lezcano 
Acked-by: Maxime Ripard 
Signed-off-by: Greg Kroah-Hartman

clockevents/tcb_clksrc: Prevent disabling an already disabled clock

2016-03-03T23:07:15+00:00

commit f02b4b72d12cbae7020a959e2ed0410a464b4cc4 upstream.

clockevents_exchange_device is calling clockevents_shutdown() on the new
clockenvents device but it may have never been enabled in the first place.
This results in the tcb clock being disabled without being enabled first:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at drivers/clk/clk.c:680 clk_disable+0x28/0x34()
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 4.4.0+ #6
Hardware name: Atmel AT91SAM9
[] (unwind_backtrace) from [] (show_stack+0x10/0x14)
[] (show_stack) from [] (warn_slowpath_common+0x78/0xa0)
[] (warn_slowpath_common) from [] (warn_slowpath_null+0x18/0x20)
[] (warn_slowpath_null) from [] (clk_disable+0x28/0x34)
[] (clk_disable) from [] (tc_shutdown+0x38/0x4c)
[] (tc_shutdown) from [] (clockevents_switch_state+0x38/0x6c)
[] (clockevents_switch_state) from [] (clockevents_shutdown+0x10/0x24)
[] (clockevents_shutdown) from [] (tick_check_new_device+0x84/0xac)
[] (tick_check_new_device) from [] (clockevents_register_device+0x7c/0x108)
[] (clockevents_register_device) from [] (tcb_clksrc_init+0x390/0x3e8)
[] (tcb_clksrc_init) from [] (do_one_initcall+0x114/0x1d4)
[] (do_one_initcall) from [] (kernel_init_freeable+0xfc/0x1b8)
[] (kernel_init_freeable) from [] (kernel_init+0x8/0xe0)
[] (kernel_init) from [] (ret_from_fork+0x14/0x24)
---[ end trace 0000000000000001 ]---

Check what state we were in before trying to disable the clock.

Fixes: cf4541c101ea ("clockevents/drivers/tcb_clksrc: Migrate to new 'set-state' interface")
Signed-off-by: Alexandre Belloni 
Cc: Nicolas Ferre 
Cc: Boris Brezillon 
Cc: linux-arm-kernel@lists.infradead.org
Cc: Daniel Lezcano 
Link: http://lkml.kernel.org/r/1452854061-30370-1-git-send-email-alexandre.belloni@free-electrons.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

clocksource/drivers/vt8500: Increase the minimum delta

2016-03-03T23:07:11+00:00

commit f9eccf24615672896dc13251410c3f2f33a14f95 upstream.

The vt8500 clocksource driver declares itself as capable to handle the
minimum delay of 4 cycles by passing the value into
clockevents_config_and_register(). The vt8500_timer_set_next_event()
requires the passed cycles value to be at least 16. The impact is that
userspace hangs in nanosleep() calls with small delay intervals.

This problem is reproducible in Linux 4.2 starting from:
c6eb3f70d448 ('hrtimer: Get rid of hrtimer softirq')

From Russell King, more detailed explanation:

"It's a speciality of the StrongARM/PXA hardware. It takes a certain
number of OSCR cycles for the value written to hit the compare registers.
So, if a very small delta is written (eg, the compare register is written
with a value of OSCR + 1), the OSCR will have incremented past this value
before it hits the underlying hardware. The result is, that you end up
waiting a very long time for the OSCR to wrap before the event fires.

So, we introduce a check in set_next_event() to detect this and return
-ETIME if the calculated delta is too small, which causes the generic
clockevents code to retry after adding the min_delta specified in
clockevents_config_and_register() to the current time value.

min_delta must be sufficient that we don't re-trip the -ETIME check - if
we do, we will return -ETIME, forward the next event time, try to set it,
return -ETIME again, and basically lock the system up. So, min_delta
must be larger than the check inside set_next_event(). A factor of two
was chosen to ensure that this situation would never occur.

The PXA code worked on PXA systems for years, and I'd suggest no one
changes this mechanism without access to a wide range of PXA systems,
otherwise they're risking breakage."

Cc: Russell King 
Acked-by: Alexey Charkov 
Signed-off-by: Roman Volkov 
Signed-off-by: Daniel Lezcano 
Signed-off-by: Greg Kroah-Hartman